Well, I'm gettin my 4.10's installed Saturday.
Got everything but the Gear oil. (yes I have the friction modifier)
What is the best stuff?
Figured I'd put the cheap ***** first, then change it after a few hundred miles.
Then I'd put in the good stuff.
Redline perhaps?
if you're using an aftermarket diff, don't use snythetic. Don't put the friction modifier in during the install either and use basic gear oil. Wait until about 500 miles of regular (easy) driving to get the gears properly worn in and then change the fluid THEN add the friction modifier and high quality fluid. (redline was my choice)
When you change the fluid after the break in period, you'll see why it was a good idea to initially not put anything expensive in (not to mention why a fluid change is reccomeded)
if you're using an aftermarket diff, don't use snythetic. Don't put the friction modifier in during the install either and use basic gear oil. Wait until about 500 miles of regular (easy) driving to get the gears properly worn in and then change the fluid THEN add the friction modifier and high quality fluid. (redline was my choice)
When you change the fluid after the break in period, you'll see why it was a good idea to initially not put anything expensive in (not to mention why a fluid change is reccomeded)
ok. still go with redline. it's more expensive but last longer and offers better friction protection. and have fun adding the fluid... Did ford engineer those axle housings to make it hard to add fluid on purpose?!?
You really have a couple directions you can go (both require a pump). I bought a cheap pump at the autoparts store that worked fine. Just make sure the gear oil is at least room temperature before you try pumping it. Personally, I would just use the same gear oil initially that you're going to use when you do the change. That way you're not mixing fluids when you do the change - you'll leave a very small residual amount in the housing. $150 or so on gears + additional parts, etc. - no reason to skimp on gear oil in my mind.
The other option is to add an aftermarket diff cover when you do the install. That way you have the drain and filler plugs on the backside - or you may want to add the cover after you change the oil - The aftermarket covers have a larger fluid capacity, end cap supports, etc.
the place you get it installed will probably put something cheap in so dont' worry about bringing in fluid.. but after 500 miles i'd try Redline.. right now i'm running Mobile 1 synthetic 75w-140 but i might try redline next time. I was told you should run the friction modifier for both.
break it in for the first 500 miles, don't go over 50 mph for the first 100, and keep the rev's down during break in and you will be guaranteed no whining